Proteomic analysis of chromate response in Staphylococcus saprophyticus isolated from a fly ash dumping site

Abstract

Staphylococci species resistant to chromate were previously isolated from a fly ash dumping site. To further understand the mechanisms developed by these bacteria to tolerate chromate, a proteomic analysis was performed to identify proteins involved in chromate stress response of Staphylococcus saprophyticus isolated from a fly ash dumping site. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and two dimensional (2D) electrophoresis gels revealed several proteins visualized as up- and down- regulated in presence of Cr (VI) (500 μg/ml). Using matrix assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS), a putative ribosome-associated protein Y [S. saprophyticus subsp. saprophyticus ATCC 15305], and a pyruvate dehydrogenase E1 component beta subunit [S. saprophyticus subsp. Saprophyticus ATCC 15305] were identified as up-regulated during chromate stress. The putative ribosome-associated protein Y is homologous to the ribosomal protein (gi24349644) expressed in Shewanella oneidensis in response to an acute chromium stress. The chromate stress upregulated pyruvate dehydrogenase from S. saprophyticus was highly similar to a pyruvate dehydrogenase (AF23026) upregulated in Staphylococcus aureus during osmotic stress. These results show that these proteins may be used as genetic systems by S. saprophyticus to resist chromate pollution and other stresses within the fly ash (FA) dumping site.

Keywords: Fly ash, chromate resistant bacteria, Staphylococci, SDS-PAGE, 2D electrophoresis

African Journal of Biotechnology Vol. 12(18), pp. 2322-2330